Remove side chat when creating new tabs

Hi mj1250 

These are called conversational tabs

Create conversational tabs - Teams | Microsoft Docs

They are typically created when tabs are created and posted in the channel such as the Tasks Tab and Excel Tab, where others comment on them. Not all tabs in Teams are conversational. From testing this afternoon they look to be persistent when moving across tabs, even across channels so if conversational tabs are open and you move to another tab which has it, the flyout remains open and just switches to another conversation.

To close it simply hit the speech bubble above it and it should disappear, and again this is persistent so it should turn off the experience across all channels and remain that way until you turn it on again or it's triggered by creating a tab. 

AFAIK, there is no way to disable them, since what you put in the side chat (conversational tab) goes back into the main channel, but you should be able to stop conversations in these places by adding channel moderation so users cannot post in that channel. 

If disabling conversational tabs is something you would like to see I would recommend opening a feedback at https://feedbackportal.microsoft.com/

Hope that helps and answers your question

Best, Chris